1. l Field of the Invention
This invention relates to effective monitoring of air traffic and to provide a pilot with hardware and method to avoid collision with other aircraft. In particular, it relates to a method and system or combination of elements which provides an on-board, constantly updated pictorial display of air traffic activity in the vicinity pertinent to an aircraft's flight. The pictorial display represents a dynamic status report on such activity which is readily interpretable by the pilot of the aircraft in monitoring his own and others' flights and for taking action should it be required to avert a collision, possible or actual.
2. Description of and Problems in the Prior Art
The present Air Traffic Control (ATC) system, as required by F.A.A. rules and regulations, is a system operated at ground facilities by personnel thereat. It employs radars for locating in three dimensions, tracking and identifying aircraft within the U.S. airspace. The sensor equipment of the ground facilities comprises two radars: a primary surveillance radar (PSR) for locating and tracking an aircraft and a secondary surveillance radar (SSR), scan-synchronized with the PSR, for interrogating and receiving signals from equipment on cooperating aircraft, such equipment being generally described as an ATC transponder system, and having ARINC characteristics to be more fully described hereinafter. The SSR interrogates aircraft and receives signals which include aircraft identity, and altitude data. These data are processed, combined with the data from the PSR and pictorially displayed at the local ATC center for use in directing air traffic activity in the local terminal control zone and throughout airspace controlled by the United States of America. The control of this traffic activity by such center is effected separately, i.e., through two-way voice radio communication with each aircraft in such control zone.
There are two distinct shortcomings of this presently used system. Data available to a pilot via an ATC center control and concerning positions of other flights in the local control zone are limited and intermittently obtained, especially in inclement weather about a busy terminal area. And secondly, a low data rate of voice communication exists between an air traffic controller in the ground facility and a pilot.
Further, although a pilot knows his own position relative to local radio navigation aids, i.e., as to VORTAC stations, marker beacons, etc., he has only an approximate definition of the positions and altitudes of other aircraft in the immediate vicinity of his own ship. He derives information on such positions of other aircraft through voice radio reports only, from either the air traffic controller who is responsible for controlling the traffic in a specific sector or the voice radio reports heard from the pilots of other aircraft. He does not communicate with such other pilots, and vice versa. Besides the chance for misunderstanding, human memory for oral information is both short and imprecise, and the volume of verbiage to which a pilot is exposed in a crowded control zone tends toward confusion in thought and possibly in action which could result in injury and damage.
These voice radio reports are made in terms of approximate geographical locations, altitudes, and times; perhaps supplemented by headings and speeds or estimates of arrival at another position and altitude. A pilot manages to some degree to sort this out in terms of distinction between traffic that may approach or intrude into the airspace he requires and that which does not represent possible collision threats outside such airspace. Even so, the burden of having to make these assessments while keeping track of his own position and status, changes to which are usually being directed continually by the air traffic controller, adds up to an appreciable work load, imposed at a time often at the end of a long and tiring flight and/or in inclement weather, when the need to concentrate on safe flying or handling of the aircraft is the greatest.
While ground air traffic controllers, using graphic displays, can almost continuously be apprised of the positions of all aircraft in a control zone, this information is available to pilots in voice radio form only, and only incrementally. Often there are relatively long waits between updates; this further increases the burden on each pilot for keeping current his mental picture of the area traffic situation, among other mental and physical duties.
The present invention overcomes these existing disadvantages without sacrificing any requirement of the F.A.A. in its communication requirements for and jurisdiction over flying aircraft in the U.S. airspace. This invention supplements the presently-existing and used ATC system, operating in concert with it yet independently of it and without interference to it or from it.